The tax imposed by this article on a motor vehicle manufacturer for the storage, use or consumption of its maintenance, support or service motor vehicles shall be levied and imposed on a monthly basis and is applied as a percentage of one thirty-ninth of the dealer net price of the motor vehicles. This tax shall not be imposed for more than thirty-nine months on any motor vehicle. Motor vehicles and component parts used in any manner for testing or development by motor vehicle manufacturers are not subject to the tax imposed pursuant to this article.
A.R.S. § 42-5158